1998 Toro 518IX starving for fuel

[dana a]

When I went to start the mower this spring the fuel pump would not prime the fuel system. I had to pour gas in the carb and start it then keep pouring gas in till it did fill the cab bowl. I mowed about half an hour and it quit running. It wouldn't start then I choked it and it started. Then it started shutting down every few minutes. I could choke it and then starts. Then it gets to the point it won't start at all. The next day I prime it again and have the same results as the day before. I put a new pump and filter on. No help. I took the gas tank off and cleaned it out and saw nothing come out and still no help. Next I thought the vent might be plugged. I took the seat and fenders off again and pulled the vent out and the little pin hole WAS plugged so I unplugged it. Put it back together and still kept quitting. Next I was going to take the carb off and see if the float was sticking. I got all the air cleaner stuff off and saw a thing on the back of the carb with an electric wire going to it. I unplugged it and tested to see if power was getting to it and it was when the key was turned on. I really don't know what this thing is but I'm thinking it is a magnet that shuts the fuel off when the key is turned off and it may have a broken wire. That probably isn't the problem because it will start several time by just applying the choke. With no choke, no start till it reaches the point that it will not start at all.
Do any of you have any ideas as to why this thing keeps stopping? I'm losing a lot of skin off my knuckles from taking this thing apart time after time, LOL!!
Thanks for any help.

 

[dana a]

Attached are a couple pictures of the wired thing on the back of the carb. What is it?

 

[Rivets]

The wire is attached to the fuel solenoid, which as you say stops the fuel flow when the key is turned off. From your description I suspect you have either an intermittent coil failure or dirty carb. The first thing I would do is, the next time it occurs immediately check for spark. If you have spark, then I would go after the carb, with a good cleaning and rebuilding. Provide us with the engine numbers so we have an idea of which carb you are talking about.

 

[slomo]

"When I went to start the mower this spring" - tells me the engine set with stale fuel over the winter.

Might want to let the engine run bone dry this coming fall. A yearly ritual is about right.

I agree, dirty carb and vacuum leaks need to be investigated first.

Second I would do a valve adjustment, clean cylinder block cooling fins ALL THE WAY AROUND the bore/s, order a foam pre-air filer if offered, install a fuel shut off valve, add an inline paper fuel filter and pull the head to de-carbonized the valves and head.

slomo

 

[dana a]

Thanks for the replies.
Rivets...........The engine is an 18 HP twin cylinder Kohler.
Engine Info--- Family SKH624U1G2RA,,,MODEL CH18S,,,SPEC #62579,,,
DISP. 624CC or 38.078 CID,,, SER.#273241450T
I replaced one of the coils 3 or 4 years ago. It had a weak spark and the exhaust temp was lower than on the other side. I don't think it is a coil or ignition issue because sometimes it will start immediately after quitting when I choke it.

slomo........when I put the mower away last fall I did like you said and let it run till it started to die then I choked it till it died, LOL, till,it died!!
The fuel pump will not prime the engine and I was thinking a vacuum leak also. I have a new hose from the crankcase to the pump. Is there any other place where a vacuum leak could be? The next thing I'm going to do is clean the cooling fins and run a hot wire to the fuel solenoid. If it still quits, cleaning the carb will be next.

 

[Rivets]

First thing I would do is remove the fuel line going to the carb and stick it in a glass jar. Crank the engine over for about 10 seconds. If you are not getting fuel in the jar, you either have a bad pump or plugged fuel line.

 

[slomo]

After Rivets suggestion I would snip the plunger off the carb solenoid if yours has one. If it fails it won't start like now.

slomo

 

[dana a]

I replaced the fuel line to the fuel pump and cleaned the cooling fins and it still quit running. Today I took the carb off and opened it up and it looked pretty clean inside. I blew compressed air thru the passages and ran small wires in all the little holes and took the fuel solenoid off and checked it and it worked OK. I did notice there is a brass sleeve in the bore of the bowl where the fuel solenoid attaches and the hole in the sleeve was not inline with the hole in the bore and half of the fuel flow was blocked off. I put it all back together and took it out for a mow and it ran for 3 1/2 hours and never offered to quit. I believe that brass sleeve was what was causing it to starve for fuel.
CASE CLOSED!!!